Many vehicles are equipped with telematics systems that collect data on the operation of the vehicle and control functions of the vehicle in response to a signal from a remote device such as a central monitoring computer or a cellular phone. Examples of data collected include a history of the locations to which the vehicle has traveled and the current status of the vehicle. Examples of functions include locking or unlocking the vehicle doors, or starting the vehicle.
The telematics system of a vehicle may be enabled both when the vehicle is active (i.e. in a key-on state) or when the vehicle is inactive (i.e. in a key-off state). The power used by the telematics system when the vehicle is inactive is desirably much less than when it is active because, in the key-on state, the battery is typically charging while the battery is not charging when the vehicle is inactive, in the key-off state.